The present invention relates to a portable type distance measuring apparatus, by which survey operation can be performed in easier manner.
In recent years, portable type distance measuring apparatuses with light wave distance measuring functions have been brought to the commercial stage. The portable type distance measuring apparatuses have been known and used in the past. However, the portable type distance measuring apparatus with the light wave distance measuring function is a high-performance distance measuring system using a reflecting prism as a target object, and it may not be adequate to simply name it as a portable type distance measuring apparatus. Also, a portable type distance measuring apparatus using an ultrasonic wave has been known, but it is low in accuracy and narrow in a range of which distance measurement can be performed, and performance characteristics are not high enough for the actual execution of survey operation.
The portable type distance measuring apparatus with the light wave distance measuring function has been produced recently for practical use. This apparatus uses a light of electro magnetic wave type and enable to measure a distance up to the target object with high accuracy using pulse number and phase of pulsed light. For the measurement of short distance (up to about 100 m), it is used as a non-prism type without using a reflecting prism as the target object. When the reflecting prism is used, distance measurement can be achieved for a long distance.
Referring to FIG. 7, description will be given below on a conventional portable type distance measuring apparatus.
A portable type distance measuring apparatus 1 is designed in such size and shape that it can be handled and carried by one hand. It is a portable type distance measuring apparatus of non-prism type without using a reflecting prism.
The portable type distance measuring apparatus 1 comprises a distance measuring unit (not shown), an azimuth finder, and a power source unit such as battery incorporated in it. A distance measuring light from the distance measuring unit is projected from a projection unit 2 provided on one surface of the portable type distance measuring apparatus 1. On upper surface of the portable type distance measuring apparatus 1, a display unit 3 and an operation unit 4 are arranged. The operation unit 4 has various types of pushbuttons such as a power switch, an operation switch, etc. By operating these pushbuttons, a distance measuring light 6 is projected from the projection unit 2 to a measurement plane 5 of a target object. As the distance measuring light 6, a visible light is used. An operator can visually confirm a projected position of the distance measuring light 6 on the measurement plane 5. The distance measuring light 6 reflected by the measurement plane 5 enters the distance measuring unit via the projection unit 2. By the distance measuring unit, a distance between the portable type distance measuring apparatus 1 and the measurement plane 5 (target object) is measured, and the result of measurement is displayed on the display unit 3.
The conventional portable type distance measuring apparatus as described above is a light wave distance measuring instrument and can measure the distance to the target object and the measurement plane with high accuracy. To provide portability, it is designed as a non-prism type. The light wave distance measuring instrument is used to measure a distance by receiving a reflection light from the measurement plane (target object), and it is used on the assumption that the measurement plane is present. In case the measurement plane is present at a position opposite to the portable type distance measuring apparatus, measurement can be made effectively. In case there is no target object, it is not possible to determine a position apart from the portable type distance measuring apparatus 1 by a given distance. Also, it is not possible to determine positions with a given spacing along the projecting direction of the distance measuring light.
Further, in case the measurement plane is a plane tilted with respect to the distance measuring light or ground surface, there are much variations on the measured values according to the properties of the surface to be projected. That is because, among the regions projected by the distance measuring light, an area with higher reflection is selected as a measuring point.
It is an object of the present invention to provide a portable type distance measuring apparatus, which can be used as a distance measuring system of a non-prism type in case there is a target object suitable for measurement, and which can be used as a distance measuring system of a prism type in case there is no target object suitable for measurement.
To attain the above object, the portable type distance measuring apparatus according to the present invention comprises an apparatus main body having a distance measuring unit for measuring a distance by projecting a distance measuring light, a control unit for controlling the distance measuring unit and for processing measurement data from the distance measuring unit and a transmitting unit to emit a communication light including the measurement data to a distance measuring direction, and a target unit having a display unit, an operation unit and a photodetection unit for receiving the communication light, wherein the target unit is removably mounted on the apparatus main body so that the target unit may be used as an object to be measured for distance measurement when necessary. Also, the present invention provides a portable type distance measuring apparatus as described above, wherein the apparatus main body further comprises a display unit and an operation unit, and the apparatus main body can be operated under condition that the target unit is separated. Further, the present invention provides a portable type distance measuring apparatus as described above, wherein each of the apparatus main body and the target unit comprises a power source unit and a control unit so that the apparatus main body and the target unit can be operated independently. Also, the present invention provides a portable type distance measuring apparatus as described above, wherein the distance measuring light also serves as the communication light, the transmitting unit comprises a modulation circuit for polymerizing the measurement data to the distance measuring light, and the target unit comprises a demodulation circuit for separating and extracting the measurement data from the distance measuring light. Further, the present invention provides a portable type distance measuring apparatus as describe above, wherein at least one of the apparatus main body and the target unit is provided with an arithmetic operation program for obtaining survey results as desired based on the distance measurement data. Also, the present invention provides a portable type distance measuring apparatus as described above, wherein the apparatus main body and the target unit are integrated with each other, and the distance measurement data is delivered and received between the apparatus main body and the target unit by the distance measuring light. Further, the present invention provides a portable type distance measuring apparatus as described above, wherein the distance measuring light is a visible light and has a pointer function. Also, the present invention provides a portable type distance measuring apparatus as described above, wherein a visible laser pointer beam is projected to a direction opposite to a projecting direction of the distance measuring light. Further, the present invention provides a portable type distance measuring apparatus as describe above, wherein a bubble tube for detecting horizontality of the distance measuring light is provided on the apparatus main body. Also, the present invention provides a portable type distance measuring apparatus as described above, wherein the bubble tube is an electric bubble tube for detecting inclination, and a tilt angle is displayed on the display unit based on an output corresponding to the inclination.